The present invention relates to telephony. More particularly, in some embodiments, the present invention relates to a system and method for monitoring, evaluating and actively managing telephone-call quality in data-network-based telephony networks.
Data networks such as the Internet are now being used to transmit voice. Such data-network-based telephony networks provide an alternative to public-switched telephone networks (xe2x80x9cPSTNsxe2x80x9d) for placing telephony calls.
FIG. 1 depicts a schematic diagram of a system 100 for voice communications over a data network in the prior art. The system includes data network 102 and public-switched telephone networks (xe2x80x9cPSTNxe2x80x9d) 120 and 122. The specifics of the architectures and communications protocols of such systems are not described herein except to note that they are quite different from one another such that direct communication therebetween is not possible. It will be appreciated that while two PSTNs (i.e., PSTN 120 and 122) are depicted, there is, at least functionally, only one worldwide PSTN.
Communication between a PSTN and a data network is implemented via a xe2x80x9cgateway.xe2x80x9d A gateway is an entrance to and an exit from a communications network. A gateway is typically an electronic repeater device that intercepts and translates signals from one network to another. A gateway often includes a signal conditioner that filters out unwanted noise and controls characters. In data networks, gateways are typically a xe2x80x9cnodexe2x80x9d on both networks that connects two otherwise incompatible networks. Thus, gateways often perform code and protocol conversions. Such an operation would be required for communication between a PSTN and a data network. Assuming an analog voice signal is delivered from the PSTN, the gateway digitizes that signal from the PSTN and encodes it and transmits it as xe2x80x9cpacketsxe2x80x9d (hereinafter xe2x80x9cdigitized voice signalxe2x80x9d) over the data network according to data network protocols. In other embodiments, the signal from the PSTN is a digital signal, such that analog-to-digital conversion is not required. Protocol conversion is still required.
An element associated with a gateway is a xe2x80x9cgatekeeper.xe2x80x9d A gatekeeper is responsible for gateway registration, address resolution and the like. A gatekeeper may be viewed as the router that directs a digitized voice signal to a xe2x80x9cterminatingxe2x80x9d gateway (i.e., a gateway that provides protocol conversion for transmission over a PSTN, for example, to a telephone). As used herein, the term xe2x80x9cgatewayxe2x80x9d includes both the gateway and gatekeeper functions.
System 100 therefore also includes gateway 110 that acts as a conduit between PSTN 120 and data network 102, and gateway 112 serving as a conduit between data network 102 and PSTN 122. The system further includes telephone 130 that is 20 connected, via link L1, to PSTN 120 and telephone 136 that is connected, via link L8, to PSTN 122. The links that are depicted in FIGS. 1 and 2 are, as is well known, trunk lines, trunk groups, etc., as appropriate.
In operation, voice message 140 from telephone 130 is transmitted over link L1 to PSTN 120. Within PSTN 120, voice message 140 is routed to switch S2 over link L2. Switch S2, the operation of which is well known in the art, will typically route voice message 140 to another switch (not shown) over a trunk group (not shown). In such a manner, voice message 140 moves through PSTN 120 being routed from switch to switch until it is carried over a final link L3 out of PSTN 120. Voice message 140 is then carried, over L4, to gateway 110. xe2x80x9cOriginatingxe2x80x9d gateway 110 performs protocol conversion and digitizes, as required, voice signal 140. Voice message 140 is then routed (the gatekeeper""s function) into data network 102. For clarity of presentation, the voice message will be assigned the same reference numeral (e.g., 140), notwithstanding the fact that the signal carrying the message is physically changed during transmission through the system.
Message 140 is transmitted over call path DNCP to (call-) xe2x80x9cterminatingxe2x80x9d gateway 112 wherein the signal leaves data network 102. Note that the designation xe2x80x9coriginatingxe2x80x9d or xe2x80x9cterminatingxe2x80x9d applies on a call-by-call basis. In other words, for a first call, a particular gateway can be an originating gateway, while for a second call, that same gateway can be a terminating gateway. Moreover, packets typically flow in both directions since both parties typically talk.
A call path through a data network, such as call path DNCP through data network 102, is not fixed according to a defined hierarchy as in a PSTN. Rather, an originating gateway xe2x80x9cselectsxe2x80x9d a terminating gateway and the voice signal is routed by successive network elements (e.g., routers, bridges, etc.) through the data network to the terminating gateway. Since routing decisions are made by each network element, call path DNCP is not a priori known or set.
Gateway 112 receives voice message 140 and converts it to a form suitable for transmission through PSTN 122. Voice message 140 is delivered over link L5 to PSTN 122. Within PSTN 122, voice message 140 is routed via over links, such as link L6, to switches, such as switch S4. Voice message 140 is carried over link L7 out of PSTN 122 to link L8 to telephone 136 to complete the call.
Such prior art systems typically suffer from significant drawbacks. Perhaps the most significant drawback is that on some data networks, such as the Internet, there are no means by which call (e.g., voice) quality is monitored and actively managed. As such, a need exists for a data-network-based telephony system that efficiently transmits telephone calls while actively managing the quality of such transmissions.
In some embodiments, the present invention provides a distributed monitoring, evaluation and routing (xe2x80x9cDiMERxe2x80x9d) system that provides active management of a data-network based telephony networks. Among other benefits, the DiMER system enhances voice quality of telephone calls that are placed over such networks.
In accordance with the present teachings, such a system, and data-network-based telephony networks incorporating the same, advantageously route calls to meet call-quality standards and/or cost goals, among other targets. Telephony networks in accordance with the present invention advantageously comprise the DiMER system, PSTNs, gateways and a data network.
In data-network-based telephony networks, problems can arise within the data network at any of a plurality of network elements, or, alternatively, at gateways themselves. Unlike PSTNs, which have a rigid, well-defined routing hierarchy, no fixed call route is a priori defined through a data network. As such, identifying a problematic network element, and rerouting to avoid such an element, is problematic.
In accordance with the present invention, the cause of problems arising within the data network is xe2x80x9cignoredxe2x80x9d for routing purposes. Rather, in the present invention, routing is addressed by focusing on the originating and terminating gateways. This approach is advantageously used because call routes over a data network to different terminating gateways are typically different. Thus, even though the route to a terminating gateway is not a priori known, whatever route is taken, that route is reasonably assumed to be uniquely associated with that gateway. As such, if compromised performance or a failed call attempt is detected, the terminating gateway (which is known) is the focus, regardless of the actual location of the problem (which can be hard to locate).
In view of the foregoing, and in accordance with the present teachings, the network is operated/administered/managed (i.e., operating goals for the network, whether they be cost, quality or other targets, are achieved) by shifting or reallocating call traffic between available terminating gateways based on system performance.
To implement such an approach, xe2x80x9cproblemxe2x80x9d gateways must be identified. In the embodiments described herein, such identification is performed by (1) obtaining call-related data (hereinafter xe2x80x9ccall metricsxe2x80x9d) from gateways via a xe2x80x9cdata acquisition element;xe2x80x9d and (2) adopting a mode of analysis that readily identifies such problem gateways. In the illustrated embodiments, the analysis function is advantageously performed by an xe2x80x9canalysis elementxe2x80x9d via a mode of analysis referred to herein as xe2x80x9cbanding.xe2x80x9d It will be understood that xe2x80x9cbanding,xe2x80x9d which is described later in this Specification, is simply one of a variety of suitable approaches for data analysis as may occur to those skilled in the art in view of the present teachings, and that such other methods may suitably be used.
Once a mode of analysis is adopted (e.g., xe2x80x9cbandingxe2x80x9d), call metrics are advantageously organized or processed into a form that is useful for that mode of analysis. Moreover, having identified xe2x80x9cproblemxe2x80x9d gateways, data must be organized in a way that facilitates shifting call traffic between acceptable gateways to meet quality standards or other goals.
To that end, and in accordance with an embodiment of the present invention, xe2x80x9cportfoliosxe2x80x9d are generated. Each portfolio indicates, for a particular xe2x80x9cDNIS,xe2x80x9d the percent allocation or routing of call-traffic to xe2x80x9cacceptablexe2x80x9d gateways (L e., gateways that can accept calls in the DNIS). Briefly, the term xe2x80x9cDNISxe2x80x9d refers to a collection of digits within a telephone number that can be used to identify telephone numbers having such digits as belonging to a particular group or xe2x80x9cdialing plan.xe2x80x9d For example, xe2x80x9c732xe2x80x9d can be a DNIS. Further description of DNIS is provided later in this Specification.
An initial call-traffic allocation within a portfolio is developed by the network administrator based on internal policy considerations (e.g., cost, quality, etc.). Changes are made in each portfolio (i.e., shifting the allocation of call traffic among the various acceptable terminating gateways) as a function of recent network performance (as indicated by the collected and processed call metrics) among any other parameters, to meet the business objectives of the network administrator. In some embodiments, such allocation is based on xe2x80x9cbest value routing,xe2x80x9d which considers both call quality and cost in the allocation calculus. Such changes are made by a xe2x80x9crouting element.xe2x80x9d
Once a new allocation is established within the portfolio, such allocation must be implemented. An illustrative methodology presented herein for implementing the revised allocation involves using historical data that provides a breakdown of call traffic for each DNIS by xe2x80x9csub-DNISxe2x80x9d (i.e., the next significant digit following the DNIS). Sub-DNIS are xe2x80x9callocatedxe2x80x9d to each gateway (i.e., telephone numbers within the sub-DNIS are routed to an appropriate gateway) as required to satisfy the desired call-traffic allocation.
Other aspects of the present invention will become clear from the following Detailed Description and the accompanying drawings.